Canon 40D/EF 100-400/Kenco 1.4 help please

[crrlb001]

Hi all,

I have searched the forums without success but forgive me if I am going over old ground. I have tried, without success, to use a Kenco 1.4 TC with my 40D and Canon 100-400L. I have taped the relevant pins to enable auto-focussing but the results have not been great. Even in good light the AF is very unreliable and is completely useless for bird photography. Does anyone have this combination working? Am I doing something wrong or am I expecting too much out of my 40D? I have noticed that there are some cracking images on here taken with Mk1s and 1.4 TCs. I have produced acceptable practice images using manual focussing buy my eyesight is not really good enough to use this in anger. any advice would be very welcome

Thanks

Barry

[Roy C]

Hi all,

I have searched the forums without success but forgive me if I am going over old ground. I have tried, without success, to use a Kenco 1.4 TC with my 40D and Canon 100-400L. I have taped the relevant pins to enable auto-focussing but the results have not been great. Even in good light the AF is very unreliable and is completely useless for bird photography. Does anyone have this combination working? Am I doing something wrong or am I expecting too much out of my 40D? I have noticed that there are some cracking images on here taken with Mk1s and 1.4 TCs. I have produced acceptable practice images using manual focussing buy my eyesight is not really good enough to use this in anger. any advice would be very welcome

Thanks

Barry
Barry, using a taped tc with the 100-400 and 400mm f5.6 worked fairly well on the 30D although AF was not as good as the bare lens. With the 40D/50D the centre focus point has been enhanced for f2.8 lenses with the consequence that the taped tc trick does not work as well.
I still use a taped tc with the 40D and 400/5.6 prime but by all account the 100-400 really struggles, especially with the centre focus point. Have you tried using one of the outer focus points? takes some getting used to but it should work better.
At the end of the day, trying to AF at what is effectively f8 is outside of the spec of all non 1 series cameras as they are only designed to AF up to f5.6.

[tdodd]

Try the outer diagonal focus points. The centre point is pretty much useless with the Kenko fitted to the 100-400.

[crrlb001]

Thanks guys - really appreciate you taking the time respond. At least there is some hope. I will give this a go tomorrow morning and let you know.

Cheers

Barry

[crrlb001]

Well, good news and bad news. The good news is that using the diagonal focus point gave a dramatic improvement in AF - it was actually useable. The bad news is that I think I will need to invest in a monopod to take any decent pictures at this sort of zoom. I'm not even sure the extra reach compensates for the loss in image quality either. I'll persevere for a while - maybe when the sun comes out - but I think this TC will rarely see the light of day. I'll hang on to it until I have convinced my wife that a 1 series is absolutely essential to the pursuit of my hobby. Probably be around the same time as the 1st international ice skating championships take place in hell.

Thanks again for the help.

Barry